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II.` S, THAYER, 0F BOSTON, MASSACHUSETTS.

Leim Patent No. 80,517, treasury 2s, 186s.l

IMPROVEMENT IN SUBMARINE EXPLOBING.

titte .donhnle namhm in tlgcse etters jntmt mit making nrt nf tige rame.

TO A LL WHOM IT MAY CONCERN:

Be it known that I, H. S. THAYEL, of Boston, in the county of Suffolk,and in the State of Massachusetts, have invented certain new and usefulImprovements in Devices for Submarine Exploring; and do hereby'deelarethat the following Vis a full, clear, and exact description thereof,reference being made to the accompanying drawings, and to tbe letters ofreference marked thereon.

In the annexed drawings, forming part of' this specification, Arepresents a. boat, raft, or other ioating body, with an opening orwell, B, through the bottom. Over this opening is constructed a totallyor partially-- darkened house or room, C. t

From the interior of this room C, one is enabled to see to a great depthbeneath the surface of the water with the naked` eye, and to a stillgreater depth by the aid of lenses. This is upon thesimple' principle oflook--` ing from a dark space into one l'essdark. By increasing theheight of this darkened room, and elevating the -stand-point of view,the power and distinctness of vision are greatly increased. It can beused in both fresh and salt water, and in both clear and cloudy weather,although a. more distinct view can be obtained when the ,sunis'shininig. i l' The advantages of this device are obvious, as by itsaid persons can ensilyscarch for lost treasures or dead bodies. It isdecidedly advantageous in coast and harbor-surveys, in any under-wateroperations, in determining the presence and movements of fish, and, byits aid,vphotographic views of the bottom or other objects under raterar'eobtained. This latter is done by placing the camera close to thesurface of the water, when, if the water is not running over fouror tivemiles an hour, bythe reflected light of the six-n a distinct negativecan be obtained.

Having thus fully described my invention, what I claim as new, anddesireto secure by LettersPatent, is

The boat A, provided with an opening, B, through its hull, and overwhich opening is placed a-darkened house, C,'as and for the purposesspecified.

In testimony that I claim the foregoing, I have 'hereunto set `my hand,this 7th day of April, 1868.

H. S. THAYER. Witnesses:

A. C. HILL, E. WATSON ARNOLD.

